# Variability in neutrophil activation

> **NIH NIH R03** · DUKE UNIVERSITY · 2020 · $80,500

## Abstract

Project Summary/Abstract
I am currently supported by a K08 (5K08-HL127183, awarded 9/4/2015) to study the biological activity of
protamine/heparin immune complexes (IC), a newly described immune complication in the cardiopulmonary
bypass population. In the course of my work, I developed a whole blood assay to measure IC-mediated neutrophil
activation, as measured by matrix metalloprotease 9 granule release. Using this assay, in a recent publication,
we report that the neutrophil response to ICs is highly variable among healthy subjects, and this variability
represents a fixed response: some individuals have neutrophils which always activate readily in the presence of
ICs, while others have neutrophils which are always minimally responsive. We have termed this susceptibility to
neutrophil degranulation, the “neutrophil activation phenotype.” In new preliminary data, we now show that the
neutrophil activation phenotype: 1) is not associated with Fc receptor variants, 2) is not limited to IC-Fc receptor
interactions and is more broadly reflective of susceptibility to neutrophil activation by a variety of receptor-
mediated agonists, 3) is determined at the cellular level and is retained with isolated neutrophils, and 4) is
correlated with propensity for NET release. Building on this strong new preliminary data, I will test the hypothesis
that the neutrophil activation phenotype is determined by differences in receptor-mediated signaling responses
and is correlated with differences in procoagulant activity. In this proposal, I will determine the cellular factors
which contribute to the neutrophil activation phenotype. In Subaim 1, I will determine if the phenotype is
associated with differences in neutrophil effector function beyond degranulation, and I will examine ROS
generation, neutrophil adherence, and ability to release proinflammatory lipid and cytokine mediators. In this
subaim, I will also quantify low density granulocytes, a subpopulation with enhanced effector functions. In Subaim
2, I will build on preliminary data demonstrating that the response to ICs is highly correlated with the response
to fMLP and to LPS, and I will determine if differences in signaling through the PI3K pathway (a point of
convergence for neutrophil Fcɣ, G-protein coupled, and Toll-like receptors) contribute to the phenotype. In
Subaim 3, I will build on preliminary data demonstrating that “high” subjects have a greater tendency to undergo
NETosis, and I will determine if this translates into differences in procoagulant activity. Specifically, I will
determine if the phenotype correlates with NET and NET component release, resistance to NET dissolution, and
thrombin generation. In completing the proposed work, I will expand on my current K08-supported research
objectives and investigate the heterogeneous neutrophil response in healthy subjects. In doing so I will continue
to develop new knowledge/skills in immunology and neutrophil biology, learn new laboratory tech...

## Key facts

- **NIH application ID:** 10064063
- **Project number:** 1R03HL144897-01A1
- **Recipient organization:** DUKE UNIVERSITY
- **Principal Investigator:** Grace Ming Lee
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $80,500
- **Award type:** 1
- **Project period:** 2020-09-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10064063

## Citation

> US National Institutes of Health, RePORTER application 10064063, Variability in neutrophil activation (1R03HL144897-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10064063. Licensed CC0.

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